Oil separator in refrigeration apparatus



March 3, 1959 o. c. OLSEN OIL SEPARATOR IN' REFRIGERATION APPARATUSFiled Oct. s, 1956 .Q Q m llllll II J Q kw m w Q h u Q S H w T J .2FIIIIII'L YEW m Q 9v 3 L I II' t Q mm QJ Q w m u n a u n h u I! Q R Q QQ t h u u um u l w 2 3 a a w mm Olaf c: ozseh. BY J M ATTORNEYS.

United States Patent OIL SEPARATOR IN REFRIGERATION APPARATUS Olaf C.Olsen, Westwood, Kans., assiguor to Clients, Inc., Kansas City, Mo., acorporation of Missouri Application October 8, 1956, Serial No. 614,578

6 Claims. (Cl. 62-192) This invention relates to refrigerating apparatusand, more particularly, to such apparatus for use in an automobile airconditioning system, and has for its principal object to provide arefrigeration apparatus with an improved arrangement for control tomaintain constant capacity for refrigeration under widely varyingoutdoor air temperatures and compressor or pump speeds.

In automobile air conditioning, it is desirable to have therefrigeration apparatus of such capacity that it will maintaincomfortable temperatures in the passenger compartment at slow or idlingspeeds as, for example, approximately 500 R. P. M. of the engine;however, in the operation of automobiles, the range of speed of theengine is from a slow or idling speed of approximately 500 R. P. M. tofull speed of approximately 4000 R. P. M. which, obviously, with adirect driven compressor provides a refrigerant output from thecompressor of many times that required to maintain maximum comfort inthe passenger compartment. In automotive air conditioning orrefrigeration, or other installations wherein the compressor or fluidpump is directly driven by the vehicle propulsion engine or other primemover having a wide variety of speeds, it has been the practice toprovide a refrigerant bypass that is opened when the required amount ofrefrigeration lowers below a selected minimum and is closed when therefrigeration requirement is above said minimum. It has also been thecommon practice to provide expensive disconnect devices such asclutches, either manual or electrical, in the compressor or pump driveso as to stop the compressor when refrigeration is not needed. Theexpensive disconnect devices in the drives are commonly used in thesystems having re frigerant gas, bypassesas the bypassing of the hot gasfrom the discharge side to the suction side of the compressor causesexcessive heating of the compressor at highfspeeds which may causeseizing of the mechanical parts of the compressor.

Further objects of the present invention are to provide a refrigeration,apparatus capable of operating at the wide range of speeds as inautomobile air conditioning that eliminates the above-nameddifiiculties; to provide a refrigeration apparatus with a compressor orpump of the rotary type capable of pumping liquid and compressing gaswith an improved arrangement in the apparatus whereby the capacity ofthe gas compressing of the compressor is varied by liquid such as oildelivered to the intake or suction side of the compressor; to provide arefrigeration apparatus with a supply of liquid lubricant carrier forthe refrigerant which supply of carrier is under pressure for deliveryto the compressor bearings and intake wih suitable controls whereby thegas capacity of the compressor is varied by the liquid that is movedtherethrough; to provide-such a refrigerating apparatus with suitablegas and liquid refrigerant bypasses to maintain constant capacity forrefrigeration at a variety of speeds of 'the compressor with a minimumof power for driving the compressor without excessive compressortemperatures; and to provide a refrigerating apparatus with suitablecon- 2,875,592 Patented Mar. 3, 1959 2 trols to maintain a suitable loadon the. compressor of the system whenever the load on the evaporator isreduced; and to provide a refrigerating apparatus that IS relativelyefficient in operation and adapted to be built in a relatively smallsize for use in an automotive vehicle and at a relatively low cost.

In accomplishing these and other objects of the present invention, Ihave provided improved details of structure, the preferred form of whichis illustrated in the accompanying drawings, wherein: a

Fig. 1 is a diagrammatical view of the refrigeration apparatus.

Fig. 2 is an enlarged diagrammaticalview of a suitable modulating typevalve in the oil line leading to the intake of the compressor.

Referring more in detail to the drawings:

1 designates a refrigerant compressor capable of pump ing liquids andpreferably of a rotary vane type which is drivingly connected to asuitable prime mover such as a vehicle engine (not shown) by a belt 2whereby when the engine is operated the compressor is driven. Thecompressor 1 discharges compressed refrigerant such as Freon gas and aliquid such as castor oil or other suitable lubricant compatible withthe refrigerant through a high pressure line 3 to a separator 4 ofsuitable construction to separate the liquid from the gas, the liquidbeing collected in a sump at the bottom of the separator as at 5 and.the gas flowing through a high pressure line 6 connecting the upperportion of the separator with a suitable condenser 7 wherein therefrigerant gas is condensed to a liquid; The condensed refrigerantflows from the condenser 7 through a line 8 to a receiver 9. A liquidrefrigerant line 10 connects the outlet of the receiver 9 with the inletof an evaporator unit 11. A conventional thermostatic ex pansion valve12 is located in the line 10 adjacent the inlet of the evaporator andcontrols the admission of refrigerant to the evaporator 11. The outletof the evaporator is connected by a low pressure line 13 to the suctionside or inlet 14 of the compressor, a check valve 15 being arranged inthe line 13 to prevent backflow therein.

The thermostatic expansion valve 12 has a thermosensitive bulb 16adjacent the outlet of the evaporator and acting through a control line17 to the valve 12 whereby an increase in the load on the evaporatorwhich results in an increase in the heat of the vapor leaving theevaporator causes the thermo-sensitive bulb to act through the controlline 17 to open the valve 12 and permit an increased flow of liquidrefrigerant to the evaporator to satisfy the load condition. A decreasein the load on the evaporator results in a decrease in. the heat of thevapor leaving same causing the bulb to act through the control line tomove the valve towards closed position and reduce the flow of liquidrefrigerant to the evaporator. A suitable valve 18 of the solenoid typeor manually operated is arranged in the line 10 between the receiver andthe thermostatic expansion valve 12 for closing said line and stoppingall flow of liquid refrigerant to the suction side or inlet 14 of thecompressor, a check valve that no refrigeration is required.

The separator 4 may be of any conventional structure but preferablyincludes a shell 19 having a perforated partition 20 therein spaced fromthe bottom 21 to define an oil sump 5 of substantial capacitytherebetween. A second perforated partition 22 is arranged in the shellin vertically spaced relation from the partition 20 and the line 3discharges into the shell 19 between the partitions 20 and 22. It ispreferred that a metal wool 23 be arranged in the shell between thepartitions 20 and 22 to facilitate removing fine oil particles from thegas delivered to the separator. Above the perforated partition 22 is afilter 24 of felt or other suitable material that will permit the gas topass therethrough but prevent the liquid or oil from passing wherebyonly gas enters the chamber 25 adjacent the upper end of the separatorwhich is in communication with the line 6. An oil line 26 is connectedwith the bottom of the separator and communicating with the oil sumptherein for flow of oil to an oil cooler 27 which has its outletconnected by a flow line 28 with the low pressure line 13 between thecheck valve 15 and the inlet 14 of the .compressor 1 and preferablyadjacent the inlet of said compressor. The lines 26 and 28 and flowcapacity of the oil cooler 27 are preferably substantially the same sizeas the high pressure line 3 whereby if only liquid is moved by thecompressor the entire output thereof may return to the suction side ofsaid compressor for continued circulation. A modulating type valve 29 isarranged in the line 28 for control of the flow of oil or liquid to thesuction side of the compressor, and an oil line 30 communicates with theline 28 between the oil cooler and valve 29 and is connected with thecompressor 1 for 'flow of oil under pressure to the bearings in saidcompressor for lubrication of same, when the structure of the compressoris such that the bearings require separate lubrication from the oilbeing pumped thereby. A suitable type of modulating. valve 29 isillustrated in Fig. 2 and includes a housing 31 having inlet 32 andoutlet 33 with a valve 34 for controlling flow therebetween. A valvespring 35 is arranged in the housing to urge the valve into closedposition. The valve has a stem 36 engaged with a diaphragm 37 loaded bya diaphragm spring 38, an adjusting screw 39 being provided to adjustthe diaphragm spring pressure for the desired loading on the diaphragm.A small passage 40 provides communication between the outlet 33 and thediaphragm chamber 41 whereby the outlet pressure acts on the diaphragmand when said outlet pressure overbalances the spring loading the valveis closed. When the outlet pressure is such that the spring loading isgreater than said pressure, the valve is opened for flow of liquidtherethrough, the valve opening being greater for increased flow inresponse to decrease of pressure at the compressor inlet. A smallpassage or bypass 42 extends from the inlet to the outlet of the valve29 for flow of liquid through the valve housing when the valve 34 isclosed, the capacity of the bypass being such that there is alwayssufficient liquid or lubricant flowing through the valve 29 and line 28to supply lubricant to the rotor of the compressor.

A bypass line 43 communicates with the high pressure line 3 and isconnected with the line 13 adjacent the inlet 14 of the compressorbetween said inlet and the check valve 15. A valve 44 is arranged in thebypass line 43 to control the flow of gas and/ or liquid from thecompressor discharge to the compressor inlet. Any suitable conventionalthermostatic or pressure controlled valve may be used as the valve 44.It is preferred, however, to use an automatic modulating type pressureactuated valve, for example, a valve having the structure of themodulating type valve 29 with the passage or bypass 42 thereof omitted.It is also preferable that the adjusting screw in the valve 44 be set toprovide slightly less loading on the diaphragm whereby slightly lesspressure on the suction side of the compressor is required before thevalve 44 opens for bypass of the gas and/ or liquid from the dischargeto the suction side of the compressor. In other words, when the pressureat the inlet of the compressor is lowered to a predetermined amount, thevalve 29 will start to open to supply more oil to the inlet of thecompressor, and then on further reduction of the. pressure at the inletof the compressor, the valve 44. will open to supplement the oil forsupplying the full capacity of the compressor. Also, the adjustingscrews of boththe valves 29 and 44 may be adjusted wherebythe sequenceof opening is reversed or only one or the other opened to supply thenecessary fluid medium for the capacity of the compressor.

If the combined medium of refrigerant gas and oil supplied to the inletof the compressor during operation is heated above a desiredtemperature, liquid refrigerant is delivered to said compressor inlet toreduce the temperature thereof. The liquid refrigerant may be taken fromany portion of the system between the condenser and evaporator. In theillustrated structure, a line 45 is connected with the liquidrefrigerant line 8 adjacent the outlet of the condenser 7 with the otherend of said line connected with the line 13 between the check valve 15and compressor inlet 14 and preferably adjacent said inlet. Aconventional thermostatic valve 46 is arranged in the line 45 to controlthe supply of liquid refrigerant delivered to the inlet of thecompressor 1. It is preferred that the valve 46 be a thermostaticexpansion valve with a thermo-sensitive bulb 47 arranged at the inlet 14of the compressor to act through a control line 48 whereby increase oftemperature at the inlet of the compressor will open the valve 46, andon decrease of the temperature the bulb 47 will react to move the valve46 toward closed position to decrease the flow of liquid refrigerantthrough the line 45.

In using a refrigerating apparatus constructed and assembled asdescribed, a quantity of lubricant is placed in the separator so as tofill the coils of the oil cooler and provide a supply in the sump of theseparator whereby said quantity is sufficient for full capacityoperation of the compressor in movement of the oil through the line 3,separator 4, cooler 27, and line 28 to the suction side of thecompressor. A suitable quantity of refrigerant is placed in the receiver9 and lines of the refrigerating system to provide an adequate supplyfor operation of the apparatus. With the refrigerating apparatus in anautomotive vehicle and the compressor 1 drivingly connected by the belt2 to the engine of the vehicle, operation of said engine drives thecompressor 1. Assuming that cooling of the passenger compartment isdesired, the valve 18 is opened and the compressor 1 draws expandedrefrigerant from the evaporator through the line 13 and check valve 15into the intake of the compressor. Simultaneously, oil is drawn throughthe passage 42 in the valve 29 and the line 28 to the intake of thecompressor to supply needed lubricant for the rotor and vanes thereof.

The compressor drives the refrigerant gas and oil at high pressurethrough the line 3 to the separator 4 where the filter 24 permits therefrigerant gas to pass into the line 6 but retains the oil whereby itis delivered to the sump 5 of the separator. The high pressurerefrigerant gas flows through the line 6 to the condenser 7 where saidrefrigerant is liquefied and the liquid flows through the line 8 to thereceiver 9 and through the line 10 to the evaporator 11 under control ofthe thermostatic expansion valve 12. When the load on the evaporatordecreases, the thermo-sensitive bulb 16 reacts to partially close thevalve 12 to reduce the flow of liquid refrigerant to the evaporator,with the result that the compressor 1 has a capacity greater than therefrigerant required to handle the load on the evaporator. Also, thevehicle may be operated at higher speeds with no material increase inthe load on the evaporator and in any of such instances there is, asubstantial reduction of the pressure at the inlet of the compressor.This reduction in pressure acts on the diaphragm of the valve 29 wherebysaid valve is opened for flow of oil from the cooler 27 through the line28 to the inlet of the compressor.

In order to obtain a minimum artificial load on the compressor, it ispreferred that the valve 29 opens relative to the reduced pressure atthe inlet of the compressor whereby the oil flowing through the line 28does not supply the full requirements of the compressor at the speedoperated resulting in further decrease of pressure at the inlet of thecompressor whereby the valve 44 opens for flow of gas and/or liquid fromthe discharge line 3 of the compressor through'the line 43 to the inletside of the compressor. If this recirculation of'the gas and liquiddischarged by the compressor in excess of the requirements of the loadon the evaporator raises the temperature of the medium at the inlet ofthe compressor to a value higher than desired, the bulb 47 reacts tostart opening the thermostatic valve 46 for flow of liquid refrigerantto the inlet of the compressor, said liquid refrigerant being evaporatedas its moves in the compressor to cool same and reducing the temperatureof the gas and liquid discharged by the compressor. The valves 12, 29,44 and 46 are all preferably of the modulating type to regulate the flowof medium therethrough in accordance with the change of the controlmedium. If the compressor 1 is stopped, or the speed thereof suddenlyreduced, whereby the pressure in the line between the check valve 15 andthe compressor inlet 14 becomes more than the pressure in the line 13upstream from the check valve 15, said check valve closes to prevent oilor liquid from backing up into the evaporator.

It is to be understood that while I have illustrated and described oneform of my invention, it is not to be limited to the specific form orarrangement of parts herein described and shown except insofar as suchlimitations are included in the claims.

What I claim and desire to secure by Letters Patent is:

1. In a refrigeration system, the combination of a condenser,arefrigerant receiver containing a supply of refrigerant, a dischargeline connecting the receiver and condenser, an expansion valve, a'lineconnecting the expansion valve and the receiver, an evaporator connectedto the expansion valve, a separator containing a supply of liquidlubricant carrier and having an inlet and a gas outlet and a liquidoutlet, a flow line connecting the gas outlet of the separator to thecondenser, a rotary refrigerant compressor adapted to pump a liquidlubricant carrier and combinations of said liquid lubricant carrier andrefrigerant gas, said compressor having an inlet and a discharge outlet,said compressor discharge outlet being connected to the separator inletfor delivering the compressor output of liquid and gas to the separatorunder pressure which acts on the liquid lubricant carrier in saidseparator, a suction line connecting the evaporator and the compressorinlet, means for governing the operation of the expansion valve inresponse to temperature in said suction line adjacent the evaporator, acheck valve in the suction line to prevent backflow from the compressorinlet to the evaporator, a flow connection between the liquid outlet ofthe separator to the suction line downstream from said check valve forflow of liquid to the compressor inlet, and means in said flowconnection partially restricting flow of liquid lubricant carrier to thecompressor inlet whereby pressure in the separator maintains flow ofsaid carrier to the compressor inlet.

2. In a refrigerating apparatus including a condenser, an evaporator, arefrigerant compressor adapted to pump liquid and combinations of liquidand refrigerant gas and discharge same under pressure, said compressorhaving an inlet and outlet, and refrigerant circulating lines betweensaid elements including a suction line connecting the evaporator to thecompressor inlet, said elements and circulating lines containing asupply of refrigerating agent, a liquid and gas separator between thecompressor outlet and the condenser containing a supply of liquidlubricant carrier for the refrigerating agent and having outlets for theseparated gas and liquid with the gas outlet connected to therefrigerant circulating line to the condenser, means controlling flow ofrefrigerant through the evaporator in response to variations in the heatload on said evaporator, a flow line between the liquid outlet of theseparator and the suction line to the compressor inlet for flow ofliquid to the compressor inlet, means in the suction line between theevaporator and the connection of said flow line to prevent flow ofliquid to the evaporator, and means in said flow line normallyrestricting flow of liquid therethrough to the compressor inlet andoperative to open for increased flow of liquid to the compressor inletin response to a predetermined reduced pressure at the inlet side of thecompressor whereby an increased quantity of liquid will be pumpedthrough the compressor to the separator and reduce the refrigerant gasoutput of said compressor.

3. In a refrigerating apparatus including a condenser, refrigerantreceiver, an evaporator, a refrigerant compressor adapted to pump liquidand combinations of liquid and refrigerant gas and discharge same underpressure, said compressor having an intake and discharge outlet, andrefrigerant circulating lines between said elements including a suctionline connecting the evaporator to the compressor inlet, said refrigerantreceiver containing a supply of refrigerating agent, a liquid and gasseparator between the compressor discharge outlet and the condensercontaining a supply of liquid lubricant carrier for the refrigeratingagent and having outlets for the separated gas and liquid with the gasoutlet connected to the refrigerant circulating, line to the condenser,means controlling fiow of refrigerant through the evaporator in responseto variationsin the heat load on said evaporator, a flow line betweenthe liquid outlet of the separator and said suction line for fiow ofliquid to the compressor inlet, means in said suction line between theevaporator and the connection of said flow line to said suction line toprevent flow of liquid to the evaporator, means in said flow linenormally restricting flow of liquid therethrough to the compressor inletand operative to open for increased flow of liquid to the compressorinlet in .response to existence of a predetermined low pressure at theinlet of the compressor whereby an increased quantity of liquid will bepumped through the compressor to the separator and reduce therefrigerant gas output of said compressor, and means bypassing the flowrestricting means in said flow line for maintaining a flow of liquidlubricant to the compressor for lubricating same.

4. In a refrigerating apparatus including a refrigerant compressorhaving an intake and a discharge outlet, said compressor being adaptedto pump both liquid and a combination of liquid and refrigerant gas anddischarge same under pressure, a liquid and gas separator containing asupply of liquid lubricant carrier for a refrigerating agent and havingoutlets for separated gas and liquid, means delivering compressed gasand liquid from said compressor to said separator, a condenser,connections between said gas outlet of the separator and the condenser,an evaporator unit, connections between said condenser and high pressureside of said evaporator unit including a thermostatically-actuatedexpansion valve having a temperature sensitive bulb adjacent the lowpressure side of said evaporator unit whereby flow through saidexpansion valve is increased in response to increased temperature at thelow pressure side of said expansion unit, a suction line between saidcompressor intake and the low pressure side of said evaporator unitincluding means spaced upstream from said compressor intake to preventbackflow toward said evaporator unit, and means responsive to variationin pressure in the suction line adjacent the compressor intake to varythe compressed gas output of the compressor while maintaining the totaloutput of said compressor, said means including a flow line between theliquid outlet of the separator and the suction line between the backfiowprevention means therein and the intake of the compressor and a valve insaid flow line operable to increase flow of liquid therethrough to thecompressor intake in response to reduced pressure at the intake of thecompressor whereby lowering of said pressure at the compressor intakeincreases the flow of liquid through said How line to said compressorintake and increases the proportion of liquid to gas in. the compressoroutput and reduces the refrigerant gas delivery therefrom.

5. In a refrigerating apparatus including a condenser, refrigerantreceiver, an evaporator and refrigerant circulating lines between saidelements, said refrigerant receiver containing a supply of refrigeratingagent, means controlling flow of refrigerant through the evaporator inan inlet and a discharge outlet with said discharge outlet 7 connectedto the separator inlet, said compressor being adapted to pump liquid andcombinations of liquid and refrigerant gas and discharge same underpressure to the separator, a flow line between the gas outlet of theseparator and condenser,a suction line between the evaporator and. thecompressor inlet, a second flow line between the liquid outlet of theseparator and the compressor inlet, a check valve in said suction lineupstream from said second flow line to prevent flow of liquid from saidsecond flow line to the evaporator, valve means in said second flow linenormally restricting flow of liquid therethrough to the compressor inletand operative to open for increased flow of liquid to the compressorinlet in response to a predetermined low pressure at the inlet of thecompressor whereby an increased quantity of liquid will be supplied tosaid compressor and increase the proportion of liquid and decrease theproportion of refrigerant gas in the compressor output, a flowconnection between the discharge outlet and the inlet of the compressor,and valve means in said flow connection and normally closing same andoperative to open for flow of gas and liquid through said flowconnection to the inlet of the compressor in response to a predeterminedpressure at the inlet of the compressor which is lower than thepredetermined pressure to which the valve means in the second flow lineis responsive.

6. In a refrigerating apparatus including a condenser, refrigerantreceiver, an evaporator, and refrigerant circulating lines between saidelements, saidrefrigerant receiver containing a supply of refrigeratingagent, means controlling flow of refrigerant through the evaporator inresponse to variation in the heat load on said evaporator, a separatorcontaining a supply of liquid lubricant carrier for the refrigeratingagent and having an inlet and a gas outlet and a liquid outlet, arefrigerant compressor having an inlet and a discharge outlet with saiddischarge outlet connected to the separator inlet, said compressor beingadapted to pump liquid and combinations of liquid and refrigerant gasand discharge same under pressure to the separator, a'flow line betweenthe gas outlet of the separator and the condenser, a suction linebetween the evaporator and the compressor inlet, a second flow linebetween the liquid outlet of the separator and the com pressor inlet, acheck valve in said suction line upstream from said second flow line toprevent flow of liquid from the second flow line to the evaporator,valve means in said second flow line normally restricting flow of liquidtherethrough to the compressor inlet and operative to open for increasedflow of liquid to the compressor inlet in response to existence of apredetermined low pressure at the inlet of the compressor whereby anincreased quantity of liquid will be supplied to said compressor andincrease the proportion of liquid and decrease the proportion ofrefrigerant gas in the compressor output, a flow connection between thecirculating lines upstream from the evaporator and the compressor inlet,and valve means in said flow connection normally in closed position andoperable to open for'fiow of refrigerant to the compressor inlet inresponse to existence of a predetermined high temperature at saidcompressor inlet.

References Cited in the file of this patent UNITED STATES PATENTS

